U.S. patent application number 12/617531 was filed with the patent office on 2010-06-17 for direct current brushless machine and wind turbine system.
Invention is credited to Mary Geddry, Gerald Sheble.
Application Number | 20100148515 12/617531 |
Document ID | / |
Family ID | 42239597 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100148515 |
Kind Code |
A1 |
Geddry; Mary ; et
al. |
June 17, 2010 |
Direct Current Brushless Machine and Wind Turbine System
Abstract
A direct current brushless electric machine is described that
comprises a sequence of permanent magnets where the N and S
magnetic poles being alternately arranged adjacent to each other,
each exerting a magnetic field; phase coils are composed of a group
of conductors, each conductor being laid essentially in parallel
with each other, each coil being displaced by a full range of a
single magnetic pole of the permanent magnet, such that each phase
coil is alternately disposed adjacent to each other; and magnetic
field or every other coil is in the same orientation to form an
armature positioned opposite to the permanent magnet movable with
respect to the armature with a predetermined amount of air gap
provided between the phase coils and the permanent magnets. The
electric machine operates as a generator when the power is flowing
from a prime mover, such as the turbine blade extracting energy
from the wind or water. The electric machine operates as a motor
when the current is applied to the coils in a sequence to move the
rotor when the turbine blades move the wind or water. Also
described is an aerodynamic system comprising inner and outer
annulus disposed driving fans, with a pressure differential flow
enhancing aerodynamic housing, able to concentrate and make laminar
rough and turbulent intake air molecule flows, creating a smooth
rotationally organized downstream vortex field, with maximum power
extraction from building structure directed velocity flow
enhancements.
Inventors: |
Geddry; Mary; (Coquille,
OR) ; Sheble; Gerald; (Buffalo Grove, IL) |
Correspondence
Address: |
MICHAEL O. SCHEINBERG
P.O. BOX 164140
AUSTIN
TX
78716-4140
US
|
Family ID: |
42239597 |
Appl. No.: |
12/617531 |
Filed: |
November 12, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12472114 |
May 26, 2009 |
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12617531 |
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12264226 |
Nov 3, 2008 |
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12472114 |
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60984965 |
Nov 2, 2007 |
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Current U.S.
Class: |
290/55 ;
310/156.01; 415/220 |
Current CPC
Class: |
F03D 1/00 20130101; Y02E
10/72 20130101; F04D 25/0606 20130101; H02K 21/225 20130101; H02K
2213/12 20130101; F03D 9/25 20160501; H02K 7/1869 20130101; F03D
1/04 20130101; H02K 41/03 20130101; Y02E 10/20 20130101; F05B
2240/33 20130101; Y02B 10/70 20130101; H02K 16/00 20130101; Y02B
10/30 20130101; F05B 2220/7066 20130101; F03B 17/061 20130101 |
Class at
Publication: |
290/55 ;
310/156.01; 415/220 |
International
Class: |
F03D 9/00 20060101
F03D009/00; H02K 21/12 20060101 H02K021/12; F03D 1/04 20060101
F03D001/04 |
Claims
1. A ducted wind turbine, comprising: a rotor shaft; multiple fan
blades extending from the rotor shaft, the fan blades causing the
shaft to rotate as wind passes between the fan blades; a rotor
positioned at the end of the fan blades away from the rotor shaft
so that the wind driving the fan blades passes between the rotor
and the rotor shaft; multiple magnets positioned on the rotor; and
a stator concentric with the rotor and including stator coils, the
stator coils positioned adjacent to the rotor.
2. The ducted wind turbine of claim 1 further comprising a vortex
inducer configurable to increase wind power at low wind speeds.
3. (canceled)
4. The ducted wind turbine of claim 1 further comprising a slip
ring for transmitting control data for the vortex inducer.
5. The ducted wind turbine of claim 1 in which the multiple magnets
are arranged with like poles facing each other in the plane of the
rotor.
6. (canceled)
7. The ducted wind turbine of claim 1 further comprising rotor
supports extending to the rotor from a collar over the rotor
shaft.
8. The ducted wind turbine of claim 1 in which the rotor is
positioned at a greater distance from the rotor shaft than is the
stator.
9. The ducted wind turbine of claim 1 further comprising multiple
rectifiers positioned on the stator, a rectifier accepting
alternating current from each pair of stator coil and delivering
rectified current to a stator bus.
10. (canceled)
11. (canceled)
12. The ducted wind turbine of claim 1 further comprising a coanda
flow enhancing air gap from which the pressure differentials induce
laminar stream flow conforming to the planar steering
structures.
13. A brushless direct current machine, comprising: a rotor
assembly including a rotor rotatable along a rotor axis; and n
rotor magnets mounted on said rotor, the magnets collectively
having 2n poles, n being an even positive integer; a stator
assembly, including a stator concentric with the rotor; m stator
coils positioned on said stator and facing said magnets in a
non-overlapping predetermined angular relationship to each other
about the axis of said rotor shaft, m being a positive integer,
said rotor magnets move adjacent to said stator coils as the rotor
rotates to form magnetic circuits; and a circuit connected with
said stator coils and being disposed on said stator between said
stator coils so as to be in non-overlapping relation to the
latter.
14. A brushless direct current machine according to claim 1 further
comprising: a circuit for detecting the rotated angular position of
the rotor and from which the current fed to the stator coils can be
controlled; and a printed circuit board disposed in a plane
parallel to said axis of the rotor shaft and extending adjacent the
end of the rotor assembly disposed nearest to said stator
assembly.
15. A brushless direct current machine according to claim 13, in
which m is more than n.
16. (canceled)
17. (canceled)
18. A brushless direct current machine according to claim 13
wherein the rotor includes a rotor shaft and wherein the end of the
rotor shaft nearest the stator assembly is clad with a conducting
material, which can be connected to a common ground for grounding
the rotor shaft.
19. A brushless direct current machine according to claim 14
wherein said detecting circuits can be comprised of at least a pair
of sensor detectors disposed on said structure, a wiring circuit so
as to be separated from each other about the axis of the rotor
shaft by an angle related by an odd integer.
20. A ducted wind turbine, comprising a brushless direct current
machine in accordance with claim 13, in which fan blades extend
from a rotor hub to the rotor.
21. A brushless D.C. machine comprising: a rotor including an
extended rotor shaft; a rotor assembly mounted on said rotor shaft;
an annular rotor magnet mounted, on said rotor assembly and having
consecutive poles spaced apart by approximately equal distances
along its circumference, thereby providing a sinusoidal pattern of
flux density with respect to the angular position of the rotor
magnet; a stator including a stator assembly and stator coils
disposed on said stator assembly so as to face said magnet in a
non-overlapping predetermined angular relationship to each other
about the axis of said rotor shaft; said rotor assembly and said
stator assembly being closely adjacent to each other at their edges
to define a relatively flat housing which contains said rotor
magnet and which forms a magnetic circuit; wiring circuits
connected with said stator coils and being disposed on said stator
assembly between said stator coils so as to be in non-overlapping
relation to the latter; and said stator coils, including the first
and second pairs of stator coils, arranged with the axis of each
coil parallel to said axis of the rotor shaft; each coil having
edges that are in leading and trailing relation with respect to the
direction of rotation of the rotor, each stator coil dimensioned so
that an angular distance about said axis of the rotor shaft between
the respective leading and trailing edges equals the angular
distance between said consecutive poles of the rotor magnet, and
said first and second pairs of stator coils, the first and second
pairs of stator coils disposed at opposite sides of said wiring
circuits, and the leading edge of one, and the trailing edge of the
other of the coils of each said pair of stator coils, being
angularly separated about said axis of the rotor shaft.cndot. by an
angular distance equal to one-half the angular distance between
said consecutive poles of the rotor magnet.
22. The brushless direct current machine of claim 21 further
comprising detecting sensors for detecting the rotated angular
position of the rotor and from which the current fed to the stator
coils can be controlled.
23. The brushless direct current machine of claim 22 in which said
detecting sensors include a pair of sensor detectors mounted on
said wiring circuits and disposed about said axis of the rotor
shaft so that the angular distance between said detectors equals
one-half the angular distance between said consecutive poles of the
rotor magnet, and the angular distance between each said detector
and the nearest edge thereto of any of said stator coils equals
one-half said angular distance between the consecutive poles of the
rotor magnet.
24. A ducted fan wind turbine, comprising the brushless direct
current machine of claim 22 and further comprising fan blades, the
rotor is positioned at the distal end of the fan blades.
25. A ducted fan wind turbine in accordance with claim 24 further
comprising a vortex generator to induce a low pressure region
behind the fan blades.
26. A method of producing wind energy comprising: providing a
direct current machine in accordance with claim 22; automatically
indexing the wind turbine; creating an enhanced double fan induced
stream flow. holding wake expansion aft of the fans open for the
longest time to enhances the flow rate of power creating air
molecules through the fans, by emulating an expanding physical duct
system, in which the air mass subsequent to transit through the
fans expands creating a volumetric pressure drop, inducing further
air flow.
Description
[0001] The application is a continuation-in-part of U.S. patent
application Ser. No. 12/472,114, filed May 26, 2009, which is a
continuation of U.S. patent application Ser. No. 12/264,226, filed
Nov. 13, 2008, which claims priority from U.S. Prov. Pat. App. No.
60/984,965, filed Nov. 2, 2007.
FIELD OF THE INVENTION
[0002] The present invention is related to electric generators and
motors, and in particular to a generator useful for generating
electricity from the wind.
BACKGROUND OF THE INVENTION
[0003] Wind is presently the fastest growing renewable energy
source, averaging annual growth rates of 29% worldwide for the last
decade. Most money and public interest invested in wind turbine
projects generally has been invested in large wind farms with multi
megawatt generating capability, even though such installations
normally occur in remote locations far from the electric power
consuming market. These remote power installations are initially
very capital intensive: utility substation systems and long range
transmission lines must be added to the installations delivering
electrical power to the end consumer. As the percentage of power
produced by big wind turbines becomes a larger percentage of total
produced electrical power, the reliability and intermittent
generating nature of wind power becomes a serious problem.
[0004] In Scandinavia, Europe, Texas, and elsewhere, the
intermittent nature of wind power requires the concurrent
construction of backup conventional power generating capacity,
which is operated at an inefficient idling rate, until required
when the wind turbine electrical output reduces from diminished
available wind.
[0005] Grid reliability questions, the high costs of power
transmission and even national security provide reasons for moving
away from centralized power production and toward wide scale
distributed power generation. While distributed energy will
contribute 11% to the US expected increase of 450,00 MW by 2025,
only 3% is from renewable sources because of issues surrounding
safe wind power generation in congested urban locations.
Distributed wind generation is held back by a lack of efficient,
reasonably priced technology.
SUMMARY OF THE INVENTION
[0006] It is an object of this invention to provide an improved
brushless direct current machine for multiple applications and to
provide an improved wind generator that can, in some embodiments,
use the DC machine as generator.
[0007] A DC machine, that is, a machine that can be used as a
direct current motor or a direct current generator, has two housing
shells assembled together forming a housing accommodating a stator
annulus, stator coils, rotor annulus, rotor magnet, and necessary
electronic circuit elements. In many embodiments, the rotor and
stator diameters are large compared to the prior art, and the large
diameter machines provide room sufficient for all necessary parts,
with the stator in fixed position operating correctly, with no
necessary trade off between rotor size and mass. Traditional rotors
are miniaturizations of the cylinders (i.e., the rotor diameter)
for high efficiency and must operate at high speeds to introduce
high relative moving magnet, stationary induction coil
velocities.
[0008] In one embodiment, the rotor is enlarged as part of the wind
annulus and has a naturally high velocity because of its large
circumference. Intrinsic high velocity and increasing inertia for
smooth operation produce nearly a sinusoid voltage before or after
rectification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an oblique front view of a fully integrated ducted
fan integrated brushless generator, turbine housing and rotating
base.
[0010] FIG. 2 is an oblique rear view of a rotor and stator
assembly, as included in the generator of FIG. 1, and also showing
the wake expansion downstream cylinder.
[0011] FIG. 3 is a cutaway plan detail view of a typical
rotor/stator section assembly showing the spatial relationship
between the moving rotor magnets, stationary inductive core, and
coil targets, with the bridge rectifiers and one of two output
busses shown.
[0012] FIG. 4 is a plane line view of rotor and stator elements
shown in circular fashion illustrating further spatial
relationships between magnet rotor elements, and the stator coil
and core flux target elements.
[0013] FIG. 5 is a planar side view of rotor and stator elements
shown in circular fashion, adding magnetic field flux lines showing
the closed flux magnetic field line relationships between moving
rotor magnets, and fixed stator elements.
[0014] FIG. 6 is a plane side view showing one stamped thin metal
segment of the multi-laminated stator structure many laminations
into the page thick, showing a representative coil as wound over
the stacked stator elements.
[0015] FIG. 7 is a top down plan view of the electrical
interconnections on the stator: inductive flux target core/coil
output wires drive bridge rectifiers which in turn drive output
busses lower buss is shown.
[0016] FIG. 8 is a side view of the rotor, stator, and axle
assembly, showing the wake stream flow augmentation control
cylinder fully open behind the fan structures.
[0017] FIG. 9 is a side view of the rotor, stator, and axle
assembly, showing the wake stream augmentation control cylinder
fully closed behind the fan structure.
[0018] FIG. 10 is a side view of the rotor, stator, and the axle
assembly showing the addition of an outer annulus fan blade system
as disposed on the outer perimeter of the rotor. This page also
shows a typical outer blade detached from the rotor perimeter, for
relative size and shape determination of the blade.
[0019] FIG. 11 is again a plan side view of the rotor, stator and
axle assembly showing the addition of index (i.e., turning the
turbine into the wind) and directionality controlling power flap
elements disposed as co-planar extensions of the basic annular
rotor shape and slope. These power flaps and accompanying air
stream flow slots enhance both instant indexing for the ducted fan
wind system, and stream flow control.
[0020] FIG. 12 is a top down plan view showing total vortex field
generalized plane air molecule stream flow lines for the entire
active ducted fan wind system, with the back of center fan disposed
flow controlling cylinder in the open position.
[0021] FIG. 13 is again a top down plan view showing total vortex
field generalized air molecule stream flow lines for the entire
active ducted fan wind system, with the back of center fan disposed
flow controlling cylinder in the closed position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] A preferred embodiment of a wind turbine in accordance with
the present invention comprises a ducted wind turbine having the
rotor and stator positioned near at end of the fan blades away from
the axis of rotation.
[0023] Ducted wind turbines include a structure near the turbine
that affects the wind flow through the turbine blades. Wind
turbines of all sizes have long been built with associated
structures and housings that provide aerodynamic features which
affect the air flow through the turbine. The Persians, several
thousand years ago, at the time of the attempted Greek conquests,
were building various cooling towers, and small open fan type
turbines, which were placed within sided structures, open in the
direction of incoming and exiting wind flow. Some early 20th
Century machines also featured housings and blade tip confinement
schemes for legitimate reduction of power limiting blade tip
vortices generated at radial right angles to the axial air
flow.
[0024] A study funded by the Carbon Trust in the UK noted the
untapped potential of roof mounted wind turbines. The study
revealed a 180% velocity gain associated with wind tumbling over
rooftops. Most importantly, since the power of the wind is
proportional to the cube of the wind velocity, volume flow gain
offers large significant benefits in power production. Although
many noted wind turbine designers, such as Hugh Piggott in Europe,
agree that properly conceived ducts can increase power production
compared to open fan turbines, many designers also believe that the
added complexity and cost of the duct structure limits the
practical application of building related small scale wind turbine
designs.
[0025] Applicants have found that wind power can be efficiently
produced right at the point of power consumption, especially by
smaller ducted fan wind turbines operated that take advantage of
the wind flow around commercial and residential structures, where
wind stream flow is naturally turbulent and requires efficient
aerodynamic features.
[0026] In accordance with one aspect of some embodiments of the
invention, a brushless DC generator is provided that is free of the
conventional machine drawbacks described above and integrated
mechanically into the structure of the wind turbine.
[0027] In accordance with another aspect of some embodiments of the
invention, a brushless DC machine is provided that is relatively
flat within the wind annulus, is compact, has high yet constant
torque, and is easily and inexpensively manufactured.
[0028] In accordance with another aspect of some embodiments of
this invention, a brushless DC machine is provided in which the
rotor shaft need not be connected to the stationary parts of the
machine by a traditional yoke design.
[0029] A DC machine is described having two housing shells
assembled together forming a housing accommodating a stator
annulus, stator coils, rotor annulus, rotor magnet, and necessary
electronic circuit elements. Large diameter machines, that is,
machines having a rotor diameter of greater than one foot and more
preferably greater than two feet, and most preferably greater than
three feet or four feet, have sufficient room for all necessary
parts, with no necessary trade off between rotor size and mass.
[0030] Traditional rotors minimize the rotor diameter to improve
efficiency and must operate at high speeds to introduce high
relative velocities between the moving magnets and the stationary
induction coils. Embodiments of the invention use a rotor that is
enlarged to be part of the wind annulus, and provides a naturally
high relative velocity from a large circumference. That is, whereas
in traditional wind turbines, rotor magnets are mounted near the
axis of the turbine, in a preferred embodiment of the invention,
the rotor magnets are mounted near the outer diameter of the
turbine, away from the central axis. Intrinsic high velocity and
increasing inertia for smooth operation produce nearly a sinusoid
voltage before or after rectification. Such advantages are
difficult to achieve at the small rotor diameters of the prior art.
Further, prior art DC machines require thrust pads or an annulus
made of a specific, relatively expensive alloy. Providing an
electrical connection grounding the rotor shaft in such machines is
difficult. Such grounding is simplified embodiments of the
invention.
[0031] Prior art wind generators operated only within a limited
range of wind speeds, because too great a wind speed would generate
excessive current that would overheat the coils and too low a wind
speed failed to provide sufficient torque to start the blades
moving, without assistance. Embodiments of the invention can
provide a much wider wind speed bandwidth than traditional
generator designs. The ducted fan wind turbine into which
embodiments of the generator are fully integrated need never be
aerodynamically or electrically shut down in very high wind speeds
because heat generated by the generated current is spread over a
large area and because the current carrying components are cooled
by the high speed air flow. Some embodiments of the invention can
generate electricity at winds speeds from as low as 2 mph to 100
mph or even higher.
[0032] Embodiments of the invention typically include a brushless
DC machine comprising a rotor upon which are mounted a set of
magnets; a stator including multiple inductive coils wound around
magnetic cores and facing the rotor magnets in an overlapping
predetermined angular relation to each other about the axis of the
rotor shaft; wiring to connect the stator coils disposed on the
stator assembly in non-overlapping relation to the stator
coils.
[0033] Detecting elements, known as field sensors, can be mounted
on the stator assembly, sensing the rotational position of the
rotor magnet and providing a correspondingly modified current, fed
to the stator coils exerting such control in accordance with the
electrical angle of the rotor magnet when operated as a motor. Such
sensors are less useful when the machine is operated as a
generator. Also, in some embodiment when the system is used as a
motor, the angular position of the rotor can be determined from the
current in the various stator coils. The determination of the
angular position from the current in the stator coils is known in
the art.
[0034] From an aerodynamic performance point of view, embodiments
of the invention can provide an extremely compact, efficient,
concentric double turbine fan system, automatically self-steering
directly into the wind almost instantaneously, therefore safely
producing maximum power from velocity increased turbulent wind flow
streams. Adjacent buildings and structures deflect and reflect
stream flows, increasing intake air mass volume velocity.
[0035] Duct structures of the present invention are desirable, not
only for the aerodynamic affects, but also for blade tip safety
control and to prevent destructive ingestion of birds and
butterflies into the fan system, common in urban residential or
business environments, duct structures form a necessary complement
to the bladed fan.
[0036] Embodiments of the present invention eliminate redundant
aerodynamic structures, seeking the minimum required physical
architectural fan housing. Depending on the application,
embodiments of the invention are guided by the design principals of
absolutely safe, quiet aerodynamic operation in close proximity to
commercial and residential airflow augmenting structures. Many of
the prior art systems feature quite complex physical and mechanical
associated structures of dubious merit.
[0037] Embodiment of the present invention incorporates the
generator itself within the literal physical architecture of the
wind turbine, so that the total system is not in any way output
power limited by the generator, an important consideration where
building directed air flow velocities, and consequent power
production can be extremely high. As described above, the
electrical current limitations of past generators required the
system be shut down at high wind speeds, which is when the system
could be delivering maximum power, because the generator was unable
to handle the power.
[0038] Embodiments of the present invention describe a brushless DC
generator/motor for efficient use as an integrated ducted fan wind
generator, as a thrust motor for marine maneuvers, and for other
round generator/motor device purposes. This application
specifically describes a brushless DC generator fully integrated
into a highly efficient ducted fan wind turbine, or WT, producing a
very large yet constant torque at different speeds, made as part of
the WT aerodynamic moving surface, cylindrically flat and compact,
and capable of being easily and inexpensively manufactured.
[0039] The turbine in a preferred embodiment further combines the
rooftop flow gain effect with an additional 20% air mass velocity
gain by inducing a pressure drop or Bernoulli Effect behind the
fan. Properly situated on a rooftop or steep hillside, the turbine
can extract more power per swept surface area than any equivalent
size open bladed turbine.
[0040] The turbine in a preferred embodiment is self-indexing,
silent, and vibration free, operating comfortably in high winds and
easily managing gusting, turbulent airflow, making it suitable for
rooftop mounting and extensive use in urban settings. The fan tips
are terminated by an outer ring or annulus and can be screened to
protect birds.
[0041] The turbine in a preferred embodiment implements aerodynamic
features with a high-bandwidth direct drive DC generator designed
to operate at variable wind speeds. The generator is built into the
outer annulus making the turbine a self-contained, unitized
generator.
[0042] Referring initially to FIGS. 1 and 2, embodiments of the DC
generator of this present invention generally comprise a
rotor/stator assembly. The rotor assembly 2 is integral with the
moving cowl of the blade assembly 21, FIG. 1. A center portion of
the rotor assembly 2 is adjacent to the stator assembly 1 using a
set of bearings maintaining a minimum air gap between the
rotor/stator assembly at the circumference, consisting of an inner
sleeve, preferably of brass, and an outer housing, preferably of a
plastic synthetic resin, and having a flange for attachment to the
stator assembly prohibiting the flow of objects into the air gap.
Stator assembly 1 is fixed to a support base 5. The support base 5
includes two vertical portions that support a horizontal axle 4
running between them. The support base 5 rotates about a vertical
axis 4, allowing it to automatically face into the wind. Rotor
assembly 2 rotates about the horizontal axle 4 as wind induces
rotation of the blades 21. Stator assembly 1 is supported by spokes
12 that attach to a hub on horizontal axle 4 portion of the support
base 5. A spinner 3 is attached to the forward end of the axle 4
and improves the aerodynamic profile of the center portion of the
turbine assembly. A wake stream flow augmentation control cylinder
8, most notably shown in FIG. 2, resides behind the rotor shroud,
that is, from the direction of incoming winds, and can be induced
to change conformation such that it can increase or decrease the
amount of wind wake flow that is permitted to pass through the
shroud, thus affecting efficiency and energy generation.
[0043] The rotor 2 preferably includes an outer ring connected to
the blades 21. The ring may be in a conical shape on its exterior
surface (furthest portion from the rotor shaft axis of rotation, or
horizontal axis 4) and may have an inner surface (closer to the
horizontal axis of rotation) that is generally planar to the axis
of rotation. The rotor assembly 2 and is rotationally attached to
the horizontal axle 4 through the blade assemblies 21 which
terminate at a rotatable hub around the axle 4. The rotor magnets 6
are suitably secured on the rotor 2 at the side the stator assembly
1.
[0044] Stator assembly 1 (FIGS. 2 and 3) is shown including an
annular assembly with stator coils 7 mounted. In a preferred
embodiment, as shown on FIG. 2, there are preferably sixty stator
coils 7. As shown in more detail in the enlarged view of FIG. 3,
each coil 7 includes an inductor, in non-overlapping relation to
each other. Further, the stator coils/inductor core targets 7 are
disposed on the stator 1 with predetermined equal angles between
the pair of stator coils and the pair of magnets 6 respectively.
The stator coils 7 are wound on respective winding blocks of equal
shape and axial depth occupying equal angles about the axis of the
rotor shaft 4. The stamped steel winding blocks (reference numeral
13 of FIG. 4) are laminated steel, saturable reactor, inductive
targets, and may be secured to the circular base plate or wall of
stator assembly by non-inductive adhesives.
[0045] FIG. 3 shows further shows, in an enlarged view of a portion
of the rotor and stator assemblies, the rotor magnet 6 having a
cubic shape. FIG. 4 shows the magnets as having an even number of
magnetic poles; North poles alternating with South poles. The rotor
magnet poles are preferably circumferentially spaced at equal
angular distance, so that the rotor magnet moving magnetic flux
density is a sine wave with the rotational angle of the rotor
assembly. Flux 14 (FIG. 5) from the rotor magnets passes through
the inductor inside the stator coils, through stamped thin steel
sheets 13 make up the stator torus and back through the other
inductor and stator coil of the pair. On a leg of the stamped thin
steel sheets 13 are wound multi-layer coils 15 on the torus stator
leg element. FIG. 6 shows one stamped thin metal segment 13 of the
multi-laminated stator structure. The stator portion includes many
laminations of metal segments 13, with the stator coil 7 wrapped
over the stacked stator elements 15.
[0046] Each of the stator coils is arranged having generally
rounded edges, respectively in a squared leading and trailing
relation to rotor assembly direction. Each of the stator coils is
dimensioned with angular distance between leading and trailing
edges as equally spaced with regard to n (in which n is the number
of poles of the rotor magnet). In the illustrated example, the
rotor magnet has thirty pole pairs. The angular distance between
the leading and trailing edges of each stator coil is between
consecutive poles of the rotor magnets.
[0047] Stator coils 7 are further arranged on stator assemblies
with the trailing edges of the stator coils spaced from the leading
edges of stator coils, respectively, by electrical angles of 90
degrees. All stator coils are connected in parallel respectively,
and leads extend from each coil to bridge rectifiers 9. These
rectifiers are connected to copper annular busses 10 (only one of
two shown in FIG. 3) which are electrically isolated from the
stator by buss standoffs 22. Busses 10 then drive loading elements
matching an inverter, and following utility hookup (not shown). As
also shown in FIG. 3, the magnets 6 are retained on the rotor using
magnet retainers 11, which comprise a non-magnetic material that
will not distort magnetic flux lines (shown as reference numeral 14
in FIG. 5).
[0048] FIG. 7 shows the electrical interconnections on the stator
1. Inductive flux target core/coil output wires 16 from the stator
coils 7 connect to the rectifier bridge 9, and then to either the
positive or negative buss 10. Each stator coil includes a
rectifier.
[0049] An alternative AC embodiment, not shown, polarity inverts
every other coil pair, thus producing sinusoidal AC without any on
board rectifier connections, into a purpose built novel AC
inverter, with integrated rectification.
[0050] Sensors or elements, not shown, can be mounted on the
stator, sensing the rotational position of the rotor magnets,
angularly spaced from each other about the axis of the rotor shaft
by an electrical angle of 90 when the machine is operated as a
motor. Sensor elements can be further arranged so that each sensor
element is separated from the adjacent or trailing edge of stator
coil by an electrical angle of 90.degree., and further so that the
sensor element is separated from the leading edge of stator coil by
an electrical angle of 90.degree.. Sensor elements can be shown
schematically to operate as detectors, responding to the rotational
position of the rotor magnets, providing corresponding control
voltages to suitable control circuits, by which currents supplied
from circuits to the series connected stator coils and are
regulated or controlled.
[0051] Alternatively, also not shown, the induced inductive peaks
of the saturable reactor target coils can be easily sensed, and
modified, as an integrated, motor controller without the addition
of any ancillary sensing equipment.
[0052] An optional wiring board, not shown, may be made of a rugged
non-conducting material, such as paper impregnated with epoxy
resin, formed in rectangular configuration, facilitating the close
nesting of stator coils and wiring board on the plane wall surface
of the stator assembly, avoiding overlapping of the wiring board
and of the stator coils. The wiring board can be parallel to the
axis of the rotor shaft and the center can extend adjacent the end
of the rotor shaft provided with a ball bearing. Thus, the axial
engagement of the bearing against the center of the wiring board
provides a thrust bearing for the axial load on the shaft.
[0053] A convenient ground for the shaft can be provided by a layer
or pad of copper foil or other conductive material and be applied
to the edge of the rotor assembly then engaged by the ball bearing
of the shaft. The printed circuit on the wiring board for
connections to the stator coils are preferably arranged with
connections are all made at one end of the wiring board by lead
wires (not shown) extending through an aperture in the stator
assembly. Either a wiring board or a symmetrical buss system can
perform the obvious function of providing the necessary connections
to the stator coils and the sensor elements, and also the functions
of providing an axial bearing for rotor shaft and connecting the
latter to ground by way of a printed circuit.
[0054] The machine generator provides a constant torque independent
of the rotary position of the rotor magnets. The rotor magnet is
oriented providing a magnetic flux density varying as a sine wave
with the rotating angle of the rotor. When the stator coils and
sensor elements or detectors are arranged as described above, the
currents applied to the stator coils cause the magnetic field of
the stator assembly to interact with the magnetic field of the
rotor assembly exerting a constant rotational force on the rotor
magnet.
[0055] The force due to a magnetic field acting on a
current-carrying wire is proportional to the product of the
magnetic flux density B and the current i in the wire. Since the
rotor magnet provides a magnetic flux density varying as a sine
wave with the rotational position of the rotor magnet, and since
coils are respectively spaced from each other by half the angular
distance between consecutive magnetic poles of the rotor magnet,
that is, by an electrical angle of 90 degrees, the magnetic flux
density B, acting upon each of coils and the magnetic flux density
B2 acting on each of coils can be defined as follows:
B.sub.1=B.sub.M sin(.theta.) Equation 1
B.sub.2=B.sub.M cos(.theta.) Equation 2
[0056] .theta. is the electrical angle of rotor and BM is the
maximum value of magnetic flux density from any of the poles of
rotor magnet. Because sensor elements are separated from each other
by an electrical angle of 90.cndot., the voltages e1 and e2
obtained from sensor elements, respectively, vary with the
rotational position of rotor assembly as follows:
e.sub.1=K.sub.1 sin(.theta.) Equation 3
e.sub.2=K.sub.1 cos(.theta.) Equation 4
[0057] K1 is a constant. If currents proportional to the voltages
obtained from sensor elements are provided to coils and to coils
from current control circuits, respectively, a current i.sub.1
flowing through coils, and a current i.sub.2 flowing through coils
may be derived from equations (3) and (4) as follows:
i.sub.1=K.sub.2 sin(.theta.) Equation 5
i.sub.2=K.sub.2 cos(.theta.) Equation 6
[0058] With K2 is a constant. Assuming that the force acting on
coils is F1, and that the force acting on coils is F2; and since
the force acting on each stator coil is proportional to the product
of the magnetic flux density applied to the respective coil and the
current flowing there through, the forces F1 and F2 can be
expressed as follows:
F.sub.1=i.sub.1B.sub.1=K.sub.2B.sub.M sin.sup.2(.theta.) Equation
7
F.sub.2=i.sub.2B.sub.2=K.sub.2B.sub.M cos.sup.2(.theta.) Equation
8
[0059] Accordingly, the total force applied to the rotor assembly
is the sum of the force from each coil:
F T = F 1 + F 2 = K 2 B M sin 2 ( .theta. ) + K 2 B M cos 2 (
.theta. ) = K 2 B M ( sin 2 ( .theta. ) + cos 2 ( .theta. ) ) = K 2
B M Equation 9 ##EQU00001##
[0060] Thus, equation (9) reveals that the rotational force F
applied to rotor assembly 11 is a constant independent of the
electrical angle .theta. and hence independent of the rotary angle,
of rotor assembly. Therefore, the DC machine according to this
invention provides a smooth rotation, free from the fluctuations in
torque. Further, in the described DC machine, the current flowing
through each stator coil is not switched, as in the prior art, but
is modified continuously, so that there is no noise or mechanical
sound associated with the supplying of current to stator coils.
[0061] Since the number of stator coils may be small as compared
with the number of magnetic poles on rotor magnet, it is possible
to arrange the stator coils in non-overlapping relation to each
other. Also, the stack of windings for each stator coil can be made
in a single stage. Therefore, the axial distance between rotor
magnet and stator assembly, and hence the thickness of the machine,
can be reduced. This reduction in dimension results in an increased
density of magnetic flux, therefore, this generator invention
provides a torque equivalent to, or higher than a generator having
a relatively larger number of stator coils arranged in overlapping
relation to each other, formed in winding stacks of several stages.
The preferred number of coil/inductor structures is equal to the
number of magnetic poles.
[0062] Because the stator winding blocks are arranged on stator
assembly in non-overlapping relation to each other and to the
wiring board, the axial distance between rotor magnet and stator
assemblies is not related to the thickness of wiring board. Thus,
this invention provides a machine relatively flatter than prior art
machines in which winding blocks for stator coils are disposed on a
wiring board. The density of the magnetic flux, and hence the
torque, are further increased by this reduction in axial distance
between rotor magnet and stator assembly. Further, since each
stator coil consists of winding stacks in one stage, and the axial
dimensions for the four stator winding blocks are equal, the gap
between rotor magnet and the winding blocks can be easily and
precisely determined, thereby simplifying assembly.
[0063] In the illustrated embodiment, the winding of stator coils
on winding blocks can be contrasted with a typical prior art
brushless DC machine, in which the coils are wound directly on the
stator assembly and/or other fixed members. By winding the stator
coils on individual winding blocks simply attached to stator
assembly, the precise positioning of the stator coils can be
achieved economically and without difficulty.
[0064] The invention is not limited to the embodiment shown in the
drawings. For instance, magnets may be placed on either side of the
coils or magnets may be placed on both sides of the coils. Further
a generator can be built having a two-pole rotor magnet, and a
stator having two stator coils separated from each other by an
electrical angle of 90.degree. with the stator coils being in
non-overlapping relation to each other. Even when the rotor magnet
has a greater number of poles, for example, more than eight, the
number of stator coils can be selected so that the stator coils do
not overlap each other, and such coils arranged so that those not
connected in series with each other are separated from each other
by an odd multiple of an electrical angle of 90.degree..
[0065] It is also possible in connecting rotor shaft to ground, to
electrically connect the stator assembly so that the stator
assembly is also grounded.
[0066] FIG. 8 shows a side view of the rotor, stator, and axle
assembly, showing the wake stream flow augmentation control
cylinder 8, fully open behind the fan structures. Wake stream flow
augmentation control cylinder 8 can be a Von Karman vortex street
generator. The opening of the vortex generator is opened or closed
by an actuator mechanism, such as worm screw turned by an electric
motor. At low wind speeds, the control cylinder 8 is operated in
the half opened position to form a low-pressure region behind the
fan, increasing the air flow through the fan. FIG. 9 shows the same
elements as FIG. 8, but with the control cylinder closed for use at
higher wind velocities, indicated by wake stream flow lines 17.
[0067] FIG. 10 shows a side view of the rotor 2, stator 1, and the
axle assembly showing the addition of an outer annulus fan blade
system 18 disposed on the outer perimeter of the rotor 2. The outer
blades 18 reduce frictional drag on the rotor by creating vortices
as turbine spins. If the outer blades are sufficiently high, they
also provide additional surface area to pick up wind, like
additional fan blades. Short blades, for example about one inch
high, would reduce drag but not provide much additional torque.
Longer blades, such as a foot high, would also provide additional
torque.
[0068] FIG. 11 shows angled steering and power output augmentation
flaps 19. The aerodynamic principles in use here are as
follows:
[0069] The flaps represented are co-planar extensions of the rotor
angle shape. As such, by deflecting a volume of air outward, each
flap 19 in turn exerts a rotational torque through the rigid
linking arms inward. For example, if the upper flap at the top of
the drawing were angled outward at a steeper deflectional angle,
the entire wind turbine system would rotate clockwise. The value of
the system from a precise steering/indexing point of view is that
it is balanced and differential, exerting a tremendous amplified
torque on the center mount.
[0070] The COANDA aperture 20 causes the streamflow after the
angled rotor shape to track and conform to the inside of the power
flap, thus using both the inside and the outside of the power flaps
to control both steering or "automatic indexing", while holding the
wake open, maintaining the virtual pressure difference between
inner and outer wake flows aft of the fan. The flaps induce a
virtual wall behind the fan forcing the air to try and equalize the
pressure by flowing only through the fan.
[0071] FIG. 12 shows the total vortex field generalized plane air
molecule stream flow lines 17 for the entire active ducted fan wind
system, with the back of center fan disposed flow controlling
cylinder in the open position.
[0072] FIG. 13 is again a top down plan view showing total vortex
field generalized air molecule stream flow lines 17 for the entire
active ducted fan wind system, with the back of center fan disposed
flow controlling cylinder in the closed position.
[0073] Embodiments of the present invention may contrast the single
vertical stabilizer as often used in wind turbines with the
balanced differential design. In such a system having a traditional
vertical stabilizer, the extended flat plane of the stabilizer
divides the stream flow. If the stream flow is unequal, then the
pressure on either side of the stabilizer is unequal, thus turning
the attached fan into the direction of low pressure.
[0074] In the embodiment as shown in FIG. 11, the long lever arms
of the angled complementary flaps 19 multiply the indexing torque
of the double steering flaps, which have potentially double the
surface area of a conventional vertical stabilizer. Very rapid
automatic, self steering, accurate indexing is very desirable in
the turbulent high velocity intake stream flow associated with
turbine operation in conjunction with building and structure
shapes.
[0075] The relationship is a Newtonian Third Law relationship: the
more outwardly angled flap exerts a greater force in deflecting
more air at a sharper angle. In turn the deflected air exerts a
force on the more outwardly extended flap, trying to normalize or
make the pressure equal. This force is applied the center bearing
as a rotational torque in a clockwise direction. The deflection
force can also be stated in constructive drag terms.
[0076] Another aspect of preferred embodiments of the invention
which differs from other ducted fan wind turbines is that such
embodiments of the present invention fully integrate steering
functions with wake expansion functions. A long literal physical
duct, which would maintain the pressure drop difference in the air
behind the fans, and the outside air, inducing more air flow
through the turbine fan, would not work in the turbulent flow
environment associated with nearby structures. The structural mass
over rotational center would be high, and the directional steering
would be slow.
[0077] The concept of wake expansion behind a working fan is
sometimes called diffusion augmentation. The extended outer
steering flaps direct an outside of the center turbine fan volume
of air outward. As the outwardly directed air molecule velocity
from the sharp aerodynamic flap planar surface increases, the
associated pressure in that equivalent air molecule volume inside
of the flaps, and behind the fan, goes down. As the pressure drops
behind the fan, more air is induced through the fan to normalize or
make equivalent the total system air pressure, producing more
power. This Bernoulli principle, simply stated, means that when
velocity goes up, pressure within the stream flow goes down. This
principle is used in spray paint cans, perfume atomizers and
elsewhere.
[0078] This preferred embodiment described above represents the
minimum number of aerodynamic elements required to fully reconcile
instantaneous steering directly into the power source, the wind,
with simultaneous complete control the various pressure
environments inside and outside the working fans.
[0079] By comparison, a standard open fan is a propeller without an
airplane, with much incoming air molecule energy directed uselessly
outward along the extended blade structures, exerting no torque
force on the fan blades.
[0080] The magnetic flux density produced by the embodiment
described above is a high harmonic sinusoidally distributed field
that approximates a square wave to provide a low harmonic dc
waveform after rectification and filtering. While the embodiments
shown include a single row of magnets positioned on the rotor,
other configurations can be used. For example, a second row of
magnets could be inside the stator. The magnets could be in a row
on the outside as shown in FIG. 3, on the inside, or both on the
inside and the outside.
[0081] While a combination of a DC machine and a wind turbine are
described above, both the DC machine and the wind turbine are
believed have novel aspects, be novel
[0082] Some embodiments of the invention include a ducted wind
turbine, comprising:
[0083] a rotor shaft;
[0084] multiple fan blades extending from the rotor shaft, the fan
blades causing the shaft to rotate as wind passes between the fan
blades;
[0085] a rotor positioned at the end of the fan blades away from
the rotor shaft so that the wind driving the fan blades passes
between the rotor and the rotor shaft;
[0086] multiple magnets positioned on the rotor; and
[0087] a stator concentric with the rotor and including stator
coils, the stator coils positioned adjacent to the rotor.
[0088] In some embodiments, the ducted wind turbine of further
comprises vortex inducer configurable to increase wind power at low
wind speeds.
[0089] In some embodiments, the vortex inducer comprises a Von
Karman vortex street.
[0090] In some embodiments, the ducted wind turbine further
comprises a slip ring for transmitting control data for the vortex
inducer.
[0091] In some embodiments, the ducted wind turbine, the multiple
magnets are arranged with like poles facing each other in the plane
of the rotor.
[0092] In some embodiments, the stator coils are arranged in pairs,
each pair completing a magnetic circuit from a rotor magnet as the
rotor magnet is facing the pair of stator coils.
[0093] In some embodiments, the ducted wind turbine further
comprises rotor supports extending to the rotor from a collar over
the rotor shaft.
[0094] In some embodiments, the rotor is positioned at a greater
distance from the rotor shaft than is the stator.
[0095] In some embodiments, the ducted wind turbine of claim 1
further comprising multiple rectifiers positioned on the stator, a
rectifier accepting alternating current from each pair of stator
coil and delivering rectified current to a stator bus.
[0096] In some embodiments, the wind turbine generated power at
wind speeds of between 2 mph and 100 mph.
[0097] In some embodiments, the ducted wind turbine of claim 1
further comprises a structure for automatic indexing of the ducted
wind turbine.
[0098] In some embodiments, the ducted wind turbine of claim 1
further comprises a coanda flow enhancing air gap from which the
pressure differentials induce laminar stream flow conforming to the
planar steering structures.
[0099] Some embodiments of the invention include a brushless direct
current machine, comprising:
[0100] a rotor assembly including
[0101] a rotor rotatable along a rotor axis; and
[0102] n rotor magnets mounted on said rotor, the magnets
collectively having 2n poles, n being an even positive integer;
[0103] a stator assembly, including
[0104] a stator concentric with the rotor;
[0105] m stator coils positioned on said stator and facing said
magnets in a non-overlapping predetermined angular relationship to
each other about the axis of said rotor shaft, m being a positive
integer,
[0106] said rotor magnets move adjacent to said stator coils as the
rotor rotates to form magnetic circuits; and
[0107] a circuit connected with said stator coils and being
disposed on said stator between said stator coils so as to be in
non-overlapping relation to the latter.
[0108] In some embodiments, the brushless direct current machine
further comprises:
[0109] a circuit for detecting the rotated angular position of the
rotor and from which the current fed to the stator coils can be
controlled; and
[0110] a printed circuit board disposed in a plane parallel to said
axis of the rotor shaft and extending adjacent the end of the rotor
assembly disposed nearest to said stator assembly.
[0111] In some embodiments, m is more than n and in other
embodiments M is less than n.
[0112] In some embodiments, the brushless direct current machine
further comprises a metallic base plate in electrical contact with
the metallic shield.
[0113] In some embodiments, the rotor includes a rotor shaft and
wherein the end of the rotor shaft nearest the stator assembly is
clad with a conducting material, which can be connected to a common
ground for grounding the rotor shaft.
[0114] In some embodiments, the detecting circuits can be comprised
of at least a pair of sensor detectors disposed on said structure,
a wiring circuit so as to be separated from each other about the
axis of the rotor shaft by an angle related by an odd integer.
[0115] In some embodiments, a ducted wind turbine comprises an
embodiment of the brushless direct current machine described above
and fan blades that extend from a rotor hub to the rotor.
[0116] In some embodiments, the invention includes a brushless D.C.
machine comprising:
[0117] a rotor including an extended rotor shaft;
[0118] a rotor assembly mounted on said rotor shaft;
[0119] an annular rotor magnet mounted on said rotor assembly and
having consecutive poles spaced apart by approximately equal
distances along its circumference, thereby providing a sinusoidal
pattern of flux density with respect to the angular position of the
rotor magnet;
[0120] a stator including a stator assembly and stator coils
disposed on said stator assembly so as to face said magnet in a
non-overlapping predetermined angular relationship to each other
about the axis of said rotor shaft;
[0121] said rotor assembly and said stator assembly being closely
adjacent to each other at their edges to define a relatively flat
housing which contains said rotor magnet and which forms a magnetic
circuit;
[0122] wiring circuits connected with said stator coils and being
disposed on said stator assembly between said stator coils so as to
be in non-overlapping relation to the latter; and
[0123] said stator coils, including the first and second pairs of
stator coils, arranged with the axis of each coil parallel to said
axis of the rotor shaft; each coil having edges that are in leading
and trailing relation with respect to the direction of rotation of
the rotor, each stator coil dimensioned so that an angular distance
about said axis of the rotor shaft between the respective leading
and trailing edges equals the angular distance between said
consecutive poles of the rotor magnet, and said first and second
pairs of stator coils, the first and second pairs of stator coils
disposed at opposite sides of said wiring circuits, and the leading
edge of one, and the trailing edge of the other of the coils of
each said pair of stator coils, being angularly separated about
said axis of the rotor shaft.cndot. by an angular distance equal to
one-half the angular distance between said consecutive poles of the
rotor magnet.
[0124] Some embodiments include sensors for detecting the rotated
angular position of the rotor and from which the current fed to the
stator coils can be controlled.
[0125] In some embodiments, the detecting sensors include a pair of
sensor detectors mounted on said wiring circuits and disposed about
said axis of the rotor shaft so that the angular distance between
said detectors equals one-half the angular distance between said
consecutive poles of the rotor magnet, and the angular distance
between each said detector and the nearest edge there to of any of
said stator coils equals one-half said angular distance between the
consecutive poles of the rotor magnet.
[0126] In some embodiment, the invention includes a method of
producing wind energy comprising:
[0127] providing a direct current machine as described above;
[0128] automatically indexing the wind turbine;
[0129] creating an enhanced double fan induced stream flow.
[0130] holding wake expansion aft of the fans open for the longest
time to enhances the flow rate of power creating air molecules
through the fans, by emulating an expanding physical duct system,
in which the air mass subsequent to transit through the fans
expands creating a volumetric pressure drop, inducing further air
flow.
[0131] Although a particular embodiment of the invention has been
described in detail herein with reference to the accompanying
drawings, the invention is not limited to that precise embodiment.
The drawings are not necessarily drawn to scale. Various changes
and modifications may be effected therein by a person skilled in
the art without departing from the scope or spirit of the invention
as defined in the appended claims.
* * * * *